Express this quotient in scientific notation: ${\frac{6.660\times 10^{-2}} {9.0\times 10^{-1}}}$
Solution: Start by collecting like terms together. $= {\frac{6.660} {9.0}} \times{\frac{10^{-2}} {10^{-1}}}$ Then divide each term separately. When dividing exponents with the same base, subtract their powers. $= 0.74 \times 10^{-2\,-\,-1}$ $= 0.74 \times 10^{-1}$ To write the answer correctly in scientific notation, the first number needs to be between $1$ and $10$ . In this case, we need to move the decimal one position to the right without changing the value of our answer. $ $ We can use the fact that $0.74$ is the same as $7.40 \div 10$ , or $7.40 \times 10^{-1}$ $ = {7.40 \times 10^{-1}} \times 10^{-1} $ $= 7.40\times 10^{-2}$